The present invention relates to an optical disk apparatus such as a compact disk apparatus, optical file apparatus or the like, and more particularly, relates to an optical disk apparatus of a configuration where a stationary optical portion and a movable optical portion of the optical pickup are separated. Efforts are progressing to shorten the access time and to have high-speed access operation in optical disk apparatus where a laser beam from a laser light source is irradiated to an optical disk. In particular, it is important to lighten the optical pickup in order to have higher access operation. However, there is a limit to the degree to which the optical pickup ca be made smaller and lighter.
With respect to this, there has been proposed a separated type of optical system pickup where the movable portion and the stationary portions are separated. FIG. 1 shows the configuration of a conventional optical disk apparatus. A stationary optical portion 1 of a separated type optical pickup of an optical disk apparatus includes a laser diode 2 that functions as a laser light source, and a beam splitter 3. A movable optical portion 4 of the separated type optical pickup is made up of a prism 6 that reflects the light beam that is irradiated from the stationary optical portion 1, and an object lens 7 that irradiates the light beam to a optical disk 5. The prism 6 has a reflecting surface 6a serving as a light receiving surface. The movable optical portion 4 is provided so that it can move linearly in the direction of the radius of the optical disk 5. In this manner, it is possible to carry out access operation at a high speed since only the movable optical portion 4 is driven.
However, in such a configuration where the stationary optical portion 1 and movable optical portion 4 are separated, the light emitting surface 3a of the beam splitter 3 of the stationary optical portion 1, the reflecting surface 6a of the prism 6 of the movable optical portion 4, and the surface of the object lens 7 are exposed to the outside. Thus, it is easy for dust and the like to adhere to these exposed portions. An optical disk apparatus to which dust is adhered has a deteriorated recording and deteriorated reproduction characteristics. In addition, the cleaning of the surface of the object lens 7 may be easy but when dust has contaminated the light emitting surface 3a of the beam splitter 3 and the reflecting surface 6a of the prism 6, it is necessary to clean them using a cotton swab which has been dipped in alcohol. Performing such cleaning must be performed by disassembling the optical disk apparatus that has been precisely assembled, since there is no space for cleaning. In addition, disassembling the optical disk apparatus involves the danger of damage to the precision portions and so it is practically impossible for such cleaning to be performed by a general user. In may be possible to provide a glass plate for protection. However, the existence of such a glass plate deteriorates, the optical characteristices.
Furthermore, it may be possible to provide a filter and fan inside the apparatus to form a dustproof structure directed to preventing the entry of dust to inside the apparatus. However, this dustproof structure increases the number of parts and involves trouble in the assembly, and cannot prevent the adhesion of dust to the exposed portions of the optical system.